1. Field of the Invention
This invention relates generally to selection of a numerical value manually by means of a selector switch knob and associated apparatus and, more particularly, to a system that can accumulate values at rates greater than the rate of generation of detent signals, thereby expediting the manual selection of a numerical value.
2. Description of the Related Art
In many activities, a numerical value must be entered in a system to provide the information needed to direct the apparatus executing the activity. For example, a flight officer of an aircraft may wish to enter a direction in the flight control system for use by an automatic navigation system, the entered numerical value being compared with the actual flight direction to permit the automatic navigation system to make appropriate correction. The entry of the numerical value is typically performed by accumulating detent signals generated as a result of the rotation of a selector switch knob past preselected selector switch locations.
A common problem with the entry of the numerical data is that the accuracy of the numerical data, determined by the numerical value changed by an incremental rotation of the selector switch knob, can be so small when compared to the range of possible numerical values, that an unacceptable amount of time can be consumed in rotating a selector switch to accumulate a sufficient number of detent signals to reach a desired numerical value.
In the related art, the selector switch knob can be provided with two operational rotational positions, the pressure applied to the selector switch knob determining the current operational rotational position. One of .the operational rotational positions is a course adjustment position, permitting a plurality of unit numerical values to be accumulated for each generated detent signal, while the second rotational position permits a single unit numerical value to be accumulated for each generated rotational position resulting from rotation of the selector switch position knob. The use of the selector switch with two operational rotational positions solves the problem of the rapid entering of numerical values. However, this functionality is provided by using a more complex selector switch and reduced flexibility.
A need has therefore been felt for a selector switch and associated apparatus that will permit the entering of a wide range of numerical values relative to the incremental numerical value without excessive rotation of the selector switch knob.